1. Field of the Invention
This invention relates generally to intake air cleaners for internal combustion engines and more particularly to an improved air cleaner for engine powered vehicles, especially trucks and other relatively large motor vehicles.
2. Prior Art
Engine powered vehicles have an intake air cleaner which filters the intake air to the engine before the air reaches the fuel input means, i.e. carburetor or fuel injectors. This air cleaner includes an air filter through which the intake air passes and which removes from the air entrained dust and other particulates that can clog carburetor and fuel injector fuel ports, cause excessive engine wear, and otherwise damage the engine.
Engine air cleaners, particularly those designed for use on trucks and other large vehicles, must satisfy several essential requirements. The foremost of these, of course, is highly effective air filtering capability down to the smallest particle size which the engine may ingest in use. Satisfaction of this requirement necessitates not only a highly effective air filter in the air cleaner but also effective sealing of the filter to the air cleaner housing so as to prevent leakage of unfiltered air past the filter.
Another air cleaner requirement is sufficiently high air through flow capacity to efficiently satisfy the engine air intake requirements when running at top engine speed, even after a period of engine operation at least equal to the contemplated useful life of the air cleaner filter. In the case of large vehicles, such as trucks and the like, whose engines require a relatively volumetric intake air flow rate, satisfaction of this requirement necessitates a relatively large air flow passage through the air cleaner and a relatively large surface area filter. As a consequence, air cleaners for such vehicles are quite large and generally mounted on the outside of the vehicle rather than within the engine compartment as in small trucks and passenger vehicles. Both mounting locations, that is outside of the vehicle and within the engine compartment, often present mounting problems, such as alignment of the air cleaner inlet and/or outlet with the engine intake air duct(s) and fitting the air cleaner within the available air cleaner mounting space.
Other considerations which are highly important to vehicle operators, particularly large truck operators who log relatively high mileage, are efficient engine operation, high fuel economy, and economical engine maintenance. Continued high engine efficiency and fuel economy require periodic replacement of the intake air filter since a dirty air filter significantly degrades engine efficiency and increases fuel consumption. In many vehicles, such as passenger vehicles, the engine air cleaner housing is permanently mounted within the engine compartment and contains a removable filter cartridge. Periodic filter replacement involves the simple task of removing a cover from the cleaner housing, replacing the dirty filter cartridge with a clean one, and replacing the cover on the housing. It is unnecessary to disconnect and reconnect any engine air ducts from and to the housing. In contrast, one of the most widely used air cleaners for trucks and other large vehicles are disposable units including a housing and a filter permanently mounted in the housing. Replacement of such an air cleaner involves disconnection of at least one engine air duct from the cleaner housing, removal of the entire air cleaner unit (housing and its contained dirty filter), replacement of the dirty unit by a clean unit (housing and its contained clean filter), and reconnection of the engine air duct(s) to the housing of the new unit.
This necessity of periodically disconnecting and reconnecting engine air duct(s) from and to the air cleaner and replacing the entire air cleaner unit including the cleaner housing and its contained air filter gives rise to two additional requirements which must be satisfied in order to provide a satisfactory truck engine air cleaner. These two requirements are maximum ease of air cleaner removal and replacement and low air cleaner replacement costs. Regarding the ease of air cleaner replacement, it is worthwhile to note that in most cases, at least the engine intake air duct(s) through which intake air flows to the engine is/are fixed and rigid. In many cases, it is difficult or impossible to precisely align the air cleaner housing with such fixed duct(s). For this reason, as well as to accommodate a size difference between the filter outlet and/or inlet and the engine air duct(s), it is necessary to utilize a flexible conduit or hose, such as a so-called hump hose, between most conventional air cleaners and the engine air duct(s). Such flexible air conduits or hoses complicate the filter installation and removal procedure, consume valuable air cleaner mounting space, and constitute additional parts which are subject to wear and periodic replacement. The air cleaner replacement cost is dependent primarily upon the purchase price of a new air cleaner. Accordingly, satisfying the vehicle operator's desire for low air cleaner replacement cost requires an air cleaner capable of manufacture at relatively low cost. The ability to use a given air cleaner on engines having different intake air duct sizes aids in reducing air cleaner manufacturing cost by reducing the number of sizes which must be manufactured and inventoried. Filter replacement inventories and costs are reduced, providing definite marketing advantage.
The prior art is replete with a vast assortment of engine air cleaners of the class described. Among the patents disclosing such air cleaners are the following: U.S. Pat. Nos. 4,350,509, 4,365,980, and 4,488,889.